Method for performing access management in a memory device, associated memory device and controller thereof, and associated electronic device

ABSTRACT

A method for performing access management in a memory device, the associated memory device and the controller thereof, and the associated electronic device are provided. The method may include: receiving a host command and a logical address from a host device; performing at least one checking operation to obtain at least one checking result, for determining whether to load a logical-to-physical (L2P) table from the NV memory to a random access memory (RAM) of the memory device, wherein the L2P table includes address mapping information for accessing the target data, and performing the at least one checking operation to obtain at least one checking result includes checking whether a first L2P-table index pointing toward the L2P table and a second L2P-table index sent from the host device are equivalent to each other; and reading the target data from the NV memory, and sending the target data to the host device.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation application of U.S. application Ser.No. 17/194,331, filed on Mar. 8, 2021, which is a continuationapplication of U.S. application Ser. No. 15/859,747, filed on Jan. 2,2018, which claims the benefit of U.S. Provisional Application No.62/568,797, filed on Oct. 6, 2017. The contents of these applicationsare incorporated herein by reference.

BACKGROUND OF THE INVENTION 1. Field of the Invention

The present invention is related to memory control, and moreparticularly, to a method and apparatus for performing access managementin a memory device.

2. Description of the Prior Art

Developments in memory technology have led to the wide application ofportable or non-portable memory devices, such as memory cards whichconform to the SD/MMC, CF, MS and XD specifications, respectively, orembedded memory devices which conform to the UFS and EMMCspecifications, respectively. Improving access control of memories inthese memory devices remains an issue to be solved in the art.

NAND flash memories may comprise single level cell (SLC) and multiplelevel cell (MLC) flash memories. In an SLC flash memory, each transistorused as a memory cell may have any of two electrical charge values,respectively representing the logic values 0 and 1. The storage abilityof each transistor used as a memory cell in an MLC flash memory may befully utilized, where the transistor may be driven by a voltage higherthan that in the SLC flash memory, and different voltage levels can beutilized to record information of at least two bits (e.g. 00, 01, 11, or10). In theory, the recording density of the MLC flash memory may reachat least twice the recording density of the SLC flash memory, and istherefore preferred by manufacturers of NAND flash memories.

Compared with the SLC flash memory, the lower cost and larger capacityof the MLC flash memory means it is more likely to be applied in memorydevices. The MLC flash memory does have instability issues, however. Toensure that access control of the flash memory in the memory devicemeets related specifications, a controller of the flash memory isusually configured to have management mechanisms to properly manage theaccess of data.

Related art memory devices with the above management mechanisms stillhave some disadvantages. For example, one of the memory devices maycomprise a random access memory (RAM) for purposes of buffering,management, etc., and the storage capacity of the RAM is typicallyinsufficient due to budget control. The related art tries to correct theproblem, but further problems (e.g. side effects) may be introduced.Hence, there is a need for a novel memory access design having robustdata access mechanism, to guarantee that a memory device can operateproperly in various situations, respectively.

SUMMARY OF THE INVENTION

It is an objective of the present invention to provide a method forperforming access management in a memory device, the associated memorydevice and the controller thereof, and the associated electronic device,in order to solve the above-mentioned problems.

It is another objective of the present invention to provide a method forperforming access management in a memory device, the associated memorydevice and the controller thereof, and the associated electronic device,in order to guarantee that the memory device can operate properly invarious situations, respectively.

It is yet another objective of the present invention to provide a methodfor performing access management in a memory device, the associatedmemory device and the controller thereof, and the associated electronicdevice, in order to solve the related art problems without introducingany side effect or in a way that is less likely to introduce a sideeffect.

At least one embodiment of the present invention provides a method forperforming access management in a memory device. The memory device maycomprise a non-volatile (NV) memory, and the NV memory may comprise atleast one NV memory element (e.g. one or more NV memory elements). Themethod may comprise: receiving a host command and a logical address froma host device, wherein the host command is a read command, and acombination of the host command and the logical address is directed to arequest of accessing target data corresponding to the logical addressfrom the NV memory; with regard to the request of accessing the targetdata corresponding to the logical address from the NV memory, performingat least one checking operation to obtain at least one checking result,for determining whether to load a logical-to-physical (L2P) table fromthe NV memory to a random access memory (RAM) of the memory device,wherein the L2P table comprises address mapping information foraccessing the target data, and performing the at least one checkingoperation to obtain at least one checking result comprises checkingwhether a first L2P-table index pointing toward the L2P table and asecond L2P-table index sent from the host device are equivalent to eachother; and reading the target data from the NV memory, and sending thetarget data to the host device.

In addition to the above method, the present invention also provides amemory device, and the memory device comprises a NV memory and acontroller. The NV memory is arranged to store information, wherein theNV memory may comprise at least one NV memory element (e.g. one or moreNV memory elements). The controller is coupled to the NV memory, and thecontroller is arranged to control operations of the memory device. Inaddition, the controller comprises a processing circuit that is arrangedto control the controller according to a plurality of host commands froma host device, to allow the host device to access the NV memory throughthe controller. For example, the controller receives a host command anda logical address from the host device, wherein the host command is aread command, and a combination of the host command and the logicaladdress is directed to a request of accessing target data correspondingto the logical address from the NV memory; with regard to the request ofaccessing the target data corresponding to the logical address from theNV memory, the controller performs at least one checking operation toobtain at least one checking result, for determining whether to load alogical-to-physical (L2P) table from the NV memory to a random accessmemory (RAM) of the memory device, wherein the L2P table comprisesaddress mapping information for accessing the target data, and duringperforming the at least one checking operation to obtain at least onechecking result, the controller checks whether a first L2P-table indexpointing toward the L2P table and a second L2P-table index sent from thehost device are equivalent to each other; and the controller reads thetarget data from the NV memory, and sends the target data to the hostdevice.

According to some embodiments, an associated electronic device is alsoprovided. The electronic device may comprise the above memory device,and may further comprise: the host device, coupled to the memory device.The host device may comprise: at least one processor, arranged forcontrolling operations of the host device; and a power supply circuit,coupled to the at least one processor, arranged for providing power tothe at least one processor and the memory device. In addition, thememory device may provide the host device with storage space.

In addition to the above method, the present invention also provides acontroller of a memory device, where the memory device comprises thecontroller and a NV memory. The NV memory may comprise at least one NVmemory element (e.g. one or more NV memory elements). In addition, thecontroller comprises a processing circuit that is arranged to controlthe controller according to a plurality of host commands from a hostdevice, to allow the host device to access the NV memory through thecontroller. For example, the controller receives a host command and alogical address from the host device, wherein the host command is a readcommand, and a combination of the host command and the logical addressis directed to a request of accessing target data corresponding to thelogical address from the NV memory; with regard to the request ofaccessing the target data corresponding to the logical address from theNV memory, the controller performs at least one checking operation toobtain at least one checking result, for determining whether to load alogical-to-physical (L2P) table from the NV memory to a random accessmemory (RAM) of the memory device, wherein the L2P table comprisesaddress mapping information for accessing the target data, and duringperforming the at least one checking operation to obtain at least onechecking result, the controller checks whether a first L2P-table indexpointing toward the L2P table and a second L2P-table index sent from thehost device are equivalent to each other; and the controller reads thetarget data from the NV memory, and sends the target data to the hostdevice.

The present invention method and apparatus can guarantee that the memorydevice can operate properly in various situations, respectively. Inaddition, the present invention method and apparatus provide a robustdata access mechanism. As a result, various goals such as optimalperformance, high security, budget control, etc. can be achieved.Additionally, the present invention method and apparatus can solve therelated art problems without introducing any side effect or in a waythat is less likely to introduce a side effect.

These and other objectives of the present invention will no doubt becomeobvious to those of ordinary skill in the art after reading thefollowing detailed description of the preferred embodiment that isillustrated in the various figures and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram of a memory device and a host device according to anembodiment of the present invention.

FIG. 2 illustrates an address mapping control scheme of a method forperforming access management in a memory device such as that shown inFIG. 1 according to an embodiment of the present invention.

FIG. 3 illustrates a dual-read control scheme of the method forperforming access management in the memory device according to anembodiment of the present invention.

FIG. 4 illustrates a host-owned information (HOI) checking controlscheme of the method for performing access management in the memorydevice according to an embodiment of the present invention.

FIG. 5 illustrates a random access memory (RAM)-sharing control schemeof the method for performing access management in the memory deviceaccording to an embodiment of the present invention.

FIG. 6 illustrates a working flow of the method for performing accessmanagement in the memory device according to an embodiment of thepresent invention.

DETAILED DESCRIPTION

I. The Memory System

FIG. 1 is a diagram of an electronic device 10 according to anembodiment of the present invention, where the electronic device 10 maycomprise a host device 50 and a memory device 100. The host device 50may comprise at least one processor (e.g. one or more processors) whichmay be collectively referred to as the processor 52, and may furthercomprise a power supply circuit 54 that is coupled to the processor 52.The processor 52 is arranged for controlling operations of the hostdevice 50, and the power supply circuit 54 is arranged for providingpower to the processor 52 and the memory device 100, and outputting oneor more driving voltages to the memory device 100. The memory device 100may be arranged for providing the host device 50 with storage space, andobtaining the one or more driving voltages from the host device 50 aspower source of the memory device 100. Examples of the host device 50may include, but are not limited to: a multifunctional mobile phone, atablet, a wearable device, and a personal computer such as a desktopcomputer and a laptop computer. Examples of the memory device 100 mayinclude, but are not limited to: a portable memory device (e.g. a memorycard conforming to the SD/MMC, CF, MS or XD specification), a solidstate drive (SSD), and various types of embedded memory devicesconforming to the UFS and EMMC specifications, respectively. Accordingto this embodiment, the memory device 100 may comprise a controller suchas a memory controller 110, and may further comprise a non-volatile (NV)memory 120, where the controller is arranged to control operations ofthe memory device 100 and access the NV memory 120, and the NV memory120 is arranged to store information. The NV memory 120 may comprise atleast one NV memory element (e.g. one or more NV memory elements), suchas a plurality of NV memory elements 122-1, 122-2, . . . , and 122-N,where “N” may represent a positive integer that is greater than one. Forexample, the NV memory 120 may be a flash memory, and the plurality ofNV memory elements 122-1, 122-2, . . . , and 122-N may be a plurality offlash memory chips or a plurality of flash memory dies, but the presentinvention is not limited thereto.

As shown in FIG. 1 , the memory controller 110 may comprise a processingcircuit such as a microprocessor 112, a storage unit such as a read-onlymemory (ROM) 112M, a control logic circuit 114, a random access memory(RAM) 116, and a transmission interface circuit 118, where the abovecomponents may be coupled to one another via a bus. The RAM 116 isimplemented by a Static RAM (SRAM), but the present invention is notlimited thereto. The RAM 116 may be arranged to provide the memorycontroller 110 with internal storage space. For example, the RAM 116 maybe utilized as a buffer memory for buffering data. In addition, theread-only memory 112M of this embodiment is arranged to store a programcode 112C, and the microprocessor 112 is arranged to execute the programcode 112C to control the access of the flash memory 120. Note that, insome examples, the program code 112C may be stored in the RAM 116 or anytype of memory. Further, a data protection circuit (not shown) in thecontrol logic circuit 114 may protect data and/or perform errorcorrection, and the transmission interface circuit 118 may conform to aspecific communications specification (e.g. the Serial AdvancedTechnology Attachment (SATA) specification, Universal Serial Bus (USB)specification, Peripheral Component Interconnect Express (PCIE)specification, embedded Multi Media Card (eMMC) specification, orUniversal Flash Storage (UFS) specification), and may performcommunications according to the specific communications specification.

In this embodiment, the host device 50 may transmit host commands andcorresponding logical addresses to the memory controller 110 to accessthe memory device 100. The memory controller 110 receives the hostcommands and the logical addresses, and translates the host commandsinto memory operation commands (which may be simply referred to asoperation commands), and further controls the NV memory 120 with theoperation commands to perform reading, writing/programing or erasingupon the memory units (e.g. data pages) having physical addresses withinthe flash memory 120, where the physical addresses correspond to thelogical addresses. When the memory controller 110 perform an eraseoperation on any NV memory element 122-n of the plurality of NV memoryelements 122-1, 122-2, . . . , and 122-N (in which “n” may represent anyinteger in the interval [1, N]), at least one block of multiple blocksof the NV memory element 122-n may be erased, where each block of theblocks may comprise multiple pages (e.g. data pages), and an accessoperation (e.g. reading or writing) may be performed on one or morepages.

II. Data Access Mechanism

According to some embodiments, the processing circuit such as themicroprocessor 112 may be arranged to control the memory controller 110according to a plurality of host commands from the host device 50, toallow the host device 50 to access the NV memory 120 through the memorycontroller 110. The memory controller 110 may store data into the NVmemory 120 for the host device 50, read the stored data in response to ahost command (e.g. one of the plurality of host commands) from the hostdevice 50, and provide the host device 50 with the data read from the NVmemory 120. In order to enhance the performance of the memory device100, the host device 50 may be designed to obtain some internalinformation of the memory device 100. The host device 50 may send backthe internal information previously obtained from the memory device 100toward the memory device 100, to allow the memory device 100 to use theinternal information just sent from the host device 50, for accessingthe stored data in the NV memory 120. As a result, the memory device 100may utilize and share a RAM of the host device 50, since the internalinformation sent from the host device 50 may have been temporarilystored in the RAM of the host device 50. The memory controller 110 (e.g.the microprocessor 112 running the program code 112C) may control theoperations of the memory device 100 according to the present inventionmethod, to guarantee that the memory device 100 can operate properly invarious situations, respectively. For example, the internal informationsent from the host device 50 may be incorrect, and the memory controller110 can detect this situation and prevent malfunction, etc. of thememory device 100. In another example, the information may be altered,and the memory controller 110 can detect this situation and prevent somesecurity issues.

FIG. 2 illustrates an address mapping control scheme of a method forperforming access management in a memory device such as that shown inFIG. 1 according to an embodiment of the present invention. Each of theNV memory elements 122-1, 122-2, . . . , and 122-N in the NV memory 120may comprise a plurality of physical blocks, and each of the physicalblocks may comprise a plurality of physical pages. Under control of theprocessing circuit such as the microprocessor 112, the memory controller110 may store a global logical-to-physical (L2P) address mapping table201 in the NV memory 120, and maintain (e.g. change and/or update) theglobal L2P address mapping table 201 according to the usage of the NVmemory 120. The global L2P address mapping table 201 may comprise aplurality of local L2P address mapping tables (labeled “L2P table” inFIG. 2 , for brevity), where a local L2P address mapping table maycomprise multiple sets of L2P address mapping information for mappinglogical addresses (e.g. addresses associated to host commands, foraccessing data stored in the NV memory 120) to physical addresses (e.g.addresses pointing toward locations of stored data within the NV memory120), respectively, and any set within the sets of L2P address mappinginformation may be mapping information (MI) for mapping a logicaladdress of a host command to a physical address of the NV memory 120.

In addition, the memory controller 110 may store (e.g. load) at leastone local L2P address mapping table (e.g. one or more local L2P addressmapping tables) of the plurality of local L2P address mapping tablesinto the RAM 116 as the temporary local L2P address mapping table 211,and maintain (e.g. change and/or update) the temporary local L2P addressmapping table 211 according to the usage of the NV memory 120. Whenneeded, the memory controller 110 may update the global L2P addressmapping table 201 according to the temporary local L2P address mappingtable 211. For better comprehension, multiple boxes labeled “MI” may beillustrated in the temporary local L2P address mapping table 211 torepresent multiple sets of L2P address mapping information therein, butthe present invention is not limited thereto. For example, one set ofthese sets of L2P address mapping information may be the mappinginformation for mapping a first logical address to a first physicaladdress. In another example, another set of these sets of L2P addressmapping information may be the mapping information for mapping a secondlogical address to a second physical address. According to someembodiments, implementation of the sets of L2P address mappinginformation in the local L2P address mapping table may vary. Forexample, any set of the sets of L2P address mapping information in thelocal L2P address mapping table may comprise a physical address, and theranking of the physical address among others of the physical addressesin the local L2P address mapping table may represent a logical address,but the present invention is not limited thereto. In another example,any set of the sets of L2P address mapping information in the local L2Paddress mapping table may comprise a logical address and a physicaladdress.

Additionally, the memory controller 110 may store an index table 212 inthe RAM 116, and maintain (e.g. change and/or update) the index table212 according to the usage of the NV memory 120. The index table 212 maycomprise a plurality of L2P-table indexes, and an L2P-table index of theplurality of L2P-table indexes may be an index for indexing an L2P tablesuch as one of the plurality of local L2P address mapping tables. Forexample, the L2P-table index may be a physical address that pointstoward the location where the L2P table is stored (e.g. a physical pagein a physical block), and the memory controller 110 may find the L2Ptable according to the L2P-table index.

According to some embodiments, the memory controller 110 may send a setof internal mapping information of the memory device 100 toward the hostdevice 50, to allow the host device 50 to own the set of internalmapping information, for enhancing performance of the memory device 100.For example, the set of internal mapping information may comprise a copyof a set of local L2P address mapping tables within the plurality oflocal L2P address mapping tables, and may further comprise the L2P-tableindexes of the set of local L2P address mapping tables, such as theL2P-table indexes pointing toward the locations where the set of localL2P address mapping tables are stored, respectively.

When the host device 50 sends a host command to access target data at alogical block address, the host device 50 may send the correspondinginternal mapping information within the set of internal mappinginformation. The corresponding internal mapping information may comprisea local L2P address mapping table having the set of L2P address mappinginformation (e.g. the MI) of the logical block address, for a purpose offinding the physical block and the physical page storing the targetdata. The corresponding internal mapping information may furthercomprise the L2P-table index of this local L2P address mapping table,such as the L2P-table indexes pointing toward the location where thislocal L2P address mapping table is stored, for a purpose of checking thecorrectness of the corresponding internal mapping information (e.g.checking whether it is true that the corresponding internal mappinginformation is not out of date and that the corresponding internalmapping information is not altered for bad intention).

The memory controller 110 may check whether the L2P-table index withinthe corresponding internal mapping information is the same as thatstored in the index table 212, to determine whether the correspondinginternal mapping information is correct. When the L2P-table index withinthe corresponding internal mapping information is the same as thatstored in the index table 212, the memory controller 110 determines thatthe corresponding internal mapping information is correct (which mayindicate that the corresponding internal mapping information is not outof date and that the corresponding internal mapping information is notaltered), and therefore the memory controller 110 may utilize this localL2P address mapping table as the reference for finding the target data;otherwise, the memory controller 110 determines that the correspondinginternal mapping information is incorrect (which may indicate that thecorresponding internal mapping information is out of date or that thecorresponding internal mapping information is altered), and thereforethe memory controller 110 may not utilize this local L2P address mappingtable as the reference for finding the target data. For the case thatthe corresponding internal mapping information is incorrect, the memorycontroller 110 may utilize its own version of internal mappinginformation, such as the correct L2P-table index in the index table 212and the local L2P address mapping table that is found through thecorrect L2P-table index in the index table 212.

FIG. 3 illustrates a dual-read control scheme of the aforementionedmethod for performing access management in the memory device such asthat shown in FIG. 1 according to an embodiment of the presentinvention. The memory controller 110 may control the memory device 100according to the dual-read control scheme in a situation where thecorresponding internal mapping information is incorrect, but the presentinvention is not limited thereto. For example, the memory controller 110may control the memory device 100 according to the dual-read controlscheme in a situation where the memory controller 110 has not sent theset of internal mapping information of the memory device 100 toward thehost device 50. For another example, the memory controller 110 maycontrol the memory device 100 according to the dual-read control schemewhen needed, no matter whether the memory controller 110 has sent theset of internal mapping information of the memory device 100 toward thehost device 50.

For better comprehension, suppose that the corresponding internalmapping information is incorrect, and therefore the memory controller110 may utilize its own version of internal mapping information, such asthe correct L2P-table index in the index table 212 and the local L2Paddress mapping table (labeled “L2P table” in FIG. 3 ) that is foundthrough the correct L2P-table index in the index table 212. For example,the memory controller 110 may read the local L2P address mapping tablethat is found through the correct L2P-table index in the index table212, and this reading operation may be regarded as the first readoperation (labeled “1^(st) read operation” in FIG. 3 ) for accessing thetarget data. As a result of the first read operation, the temporarylocal L2P address mapping table 211 may comprise the set of L2P addressmapping information (e.g. the MI) for finding the target data, such asthe set of L2P address mapping information (e.g. the MI) that maps thelogical address of the target data (e.g. the logical block address, etc.of the target data as indicated in the host command that asks for thetarget data) to the physical address (e.g. at least one physicaladdress, such as the physical block address together with the pageaddress indicating the physical page where the target data is stored).As shown in FIG. 3 , the set of L2P address mapping information such asthe MI pointing to one of the physical pages (labeled “Page”) of thephysical block (labeled “Block”) indicates that the memory controller110 can find the target data (labeled “Data”) according to the set ofL2P address mapping information (e.g. the MI). The memory controller 110may read the target data from this physical page, and this readingoperation may be regarded as the second read operation (labeled “2^(nd)read operation” in FIG. 3 ) for accessing the target data. As a resultof the second read operation, the data buffer 213 may comprise thetarget data (labeled “Data”), for being accessed by the host device 50.For example, the host device 50 may read the target data in the databuffer 213 through direct memory access (DMA).

According to some embodiments, the operation of loading theaforementioned at least one local L2P address mapping table (e.g. theone or more local L2P address mapping tables) of the plurality of localL2P address mapping tables into the RAM 116 as the temporary local L2Paddress mapping table 211 may comprise reading the local L2P addressmapping table that is found through the correct L2P-table index in theindex table 212.

FIG. 4 illustrates a host-owned information (HOI) checking controlscheme of the method for performing access management in the memorydevice according to an embodiment of the present invention. As thememory controller 110 has sent the set of internal mapping informationof the memory device 100 toward the host device 50, the set of internalmapping information in the host device 50 may be regarded as host-ownedinformation (HOI). When sending a host command such as that mentionedabove to access the target data, the host device 50 may send the set ofL2P address mapping information (e.g. the MI) together with theL2P-table index, such as the combination of the set of L2P addressmapping information (e.g. the MI) and the L2P-table index that is withinthe HOI. As a result, the memory device 100 may receive the set of L2Paddress mapping information (e.g. the MI) together with the L2P-tableindex, such as the combination of the set of L2P address mappinginformation (e.g. the MI) and the L2P-table index within the HOI, andmay store them in the host-owned information (HOI) buffer 214.

The memory controller 110 may check whether the L2P-table index in thehost-owned information buffer 214 is the same as the correct L2P-tableindex mentioned above (such as the L2P-table index in the index table212 shown in FIG. 4 ), to determine whether to utilize the set of L2Paddress mapping information (e.g. the MI) in the host-owned informationbuffer 214 as the reference for accessing the target data. When theL2P-table index in the host-owned information buffer 214 is the same asthe correct L2P-table index, the memory controller 110 may utilize theset of L2P address mapping information (e.g. the MI) in the host-ownedinformation buffer 214 as the reference for accessing the target data;otherwise (which means the set of L2P address mapping information (e.g.the MI) in the host-owned information buffer 214 may be out of date ormay be not reliable), the memory controller 110 may prevent utilizingthe set of L2P address mapping information (e.g. the MI) in thehost-owned information buffer 214 as the reference for accessing thetarget data, and may control the memory device 100 according to thedual-read control scheme shown in FIG. 3 .

As shown in FIG. 4 , both of the correct L2P-table index in the indextable 212 and the L2P-table index in the host-owned information buffer214 are pointing toward the same L2P address mapping table, since theL2P-table index in the host-owned information buffer 214 is the same asthe correct L2P-table index. In this situation, the set of L2P addressmapping information (e.g. the MI) in the host-owned information buffer214 may be reliable and is not out of date. The memory controller 110can find the target data (labeled “Data”) according to the set of L2Paddress mapping information (e.g. the MI) in the host-owned informationbuffer 214. The memory controller 110 may read the target data from thephysical page indicated by the set of L2P address mapping information(e.g. the MI) in the host-owned information buffer 214, and this readingoperation may be regarded as the single read operation (labeled “Readoperation” in FIG. 4 ) for accessing the target data. As a result of thesingle read operation, the data buffer 213 may comprise the target data(labeled “Data”), for being accessed by the host device 50. For example,the host device 50 may read the target data in the data buffer 213through DMA.

Based on the HOT checking control scheme shown in FIG. 4 , when theL2P-table index in the host-owned information buffer 214 is the same asthe correct L2P-table index, the memory controller 110 may rapidlyobtain the target data through the single read operation, which is muchfaster than multiple read operations (e.g. the first and the second readoperations). As a result, the performance of the memory device 100 isenhanced, and the overall performance of the electronic device isenhanced.

In addition, the operation of checking whether the L2P-table index inthe host-owned information buffer 214 is the same as the correctL2P-table index may prevent the memory device 100 from obtaining wrongdata (e.g. old data or invalid data) from the NV memory 120 for the hostdevice 50. Therefore, the HOI checking control scheme shown in FIG. 4may guarantee that the corresponding internal mapping information is notout of date and that the corresponding internal mapping information isnot altered for bad intention. Additionally, the probability of theoccurrence of memory system error due to wrong data may be greatlyreduced.

FIG. 5 illustrates a random access memory (RAM)-sharing control schemeof the method for performing access management in the memory deviceaccording to an embodiment of the present invention. According to thisembodiment, the host device 50 may comprise at least one processor (e.g.one or more processors) such as the processor 52, and may comprise a RAM56, where the RAM 56 may comprise a shared memory region 58. The memorycontroller 110 may provide information such as the set of internalmapping information to the host device 50, and the host device 50 maysend at least one portion (e.g. a portion or all) of the HOI toward thememory device 100 when asking for the target data (e.g. by sending thehost command such as a read command). For example, the aforementioned atleast one portion of the HOI may comprise the set of L2P address mappinginformation (e.g. the MI) together with the L2P-table index, such as thecombination of the set of L2P address mapping information (e.g. the MI)and the L2P-table index that is within the HOI. When the combination ofthe set of L2P address mapping information (e.g. the MI) and theL2P-table index that is within the HOI is correct and is not out ofdate, the memory controller 110 may control the memory device 100according to the HOI checking control scheme shown in FIG. 4 (ratherthan the dual-read control scheme shown in FIG. 3 ), to obtain thetarget data through the single read operation (labeled “Read operation”in FIG. 4 ).

Based on various control schemes of the present invention method, suchas the dual-read control scheme shown in FIG. 3 , the HOI checkingcontrol scheme shown in FIG. 4 , and the RAM-sharing control schemeshown in FIG. 5 , when the storage capacity of the RAM 116 isinsufficient (e.g. due to a limited budget design, a cost-down design,etc.), the present invention method and the associated architecture cansolve the related art problems without introducing any side effect or ina way that is less likely to introduce a side effect.

TABLE 1 L2P_Table(1) B:5, P:3 L2P_Table(2) B:5, P:4 L2P_Table(3) B:5,P:5 L2P_Table(4) B:5, P:6 L2P_Table(5) B:5, P:7 . . . . . .

TABLE 2 LBA(NL) B:6, P:0 LBA(NL + 1) B:6, P:1 LBA(NL + 2) B:6, P:2LBA(NL + 3) B:6, P:3 LBA(NL + 4) B:6, P:4 . . . . . .

Table 1 illustrates an example of the index table 212, and the notation“ . . . ” indicates that some table contents may be omitted for brevity.The L2P-table indexes {{B:5, P:3}, {B:5, P:4},{B:5, P:5},{B:5,P:6},{B:5, P:7}, . . . } in the second column of Table 1 can be taken asan example of the plurality of L2P-table indexes, where the notation“B:” may indicate that the number next to it is a block index of aphysical block, and the notation “P:” may indicate that the number nextto it is a page index of a physical page. The memory controller 110 canfind the L2P tables L2P_Table(1), L2P_Table(2), L2P_Table(3),L2P_Table(4), L2P_Table(5), etc. (such as that listed in the firstcolumn of Table 1) with aid of the L2P-table indexes {B:5, P:3},{B:5,P:4}, {B:5, P:5},{B:5, P:6}, {B:5, P:7}, etc. in the second column ofTable 1, respectively.

Table 2 illustrates an example of the L2P table L2P_Table(1), and thenotation “ . . . ” indicates that some table contents may be omitted forbrevity. The mapping information {{B:6, P:0},{B:6, P:1},{B:6, P:2},{B:6,P:3},{B:6, P:4}, . . . } in the second column of Table 2 can be taken asan example of the mapping information (MI) in the L2P tableL2P_Table(1), where the notation “B:” may indicate that the number nextto it is a block index of a physical block, and the notation “P:” mayindicate that the number next to it is a page index of a physical page.The memory controller 110 can find the data of the logical addressesLBA(NL), LBA(NL+1), LBA(NL+2), LBA(NL+3), LBA(NL+4), etc. (such as thatlisted in the first column of Table 2) with aid of the mappinginformation {B:6, P:0},{B:6, P:1},{B:6, P:2},{B:6, P:3},{B:6, P:4}, etc.in the second column of Table 2, respectively.

At a first time point, the memory controller 110 may have stored the L2Ptable L2P_Table(1) in the physical page PAGE(3) of the physical blockBLOCK(5) as indicated by the L2P-table index {B:5, P:3}, and may sendthe set of internal mapping information, including the combination ofthe mapping information {B:6, P:0} and the L2P-table index {B:5, P:3},toward the host device 50.

TABLE 3 LBA(NL) B:5, P:3 B:6, P:0

TABLE 4 L2P_Table(1) B:5, P:8 L2P_Table(2) B:5, P:4 L2P_Table(3) B:5,P:5 L2P_Table(4) B:5, P:6 L2P_Table(5) B:5, P:7 . . . . . .

TABLE 5 LBA(NL) B:6, P:5 LBA(NL + 1) B:6, P:1 LBA(NL + 2) B:6, P:2LBA(NL + 3) B:6, P:3 LBA(NL + 4) B:6, P:4 . . . . . .

Table 3 illustrates an example of the combination of the mappinginformation {B:6, P:0} and the L2P-table index {B:5, P:3} that is senttoward the host device 50 at the first time point, Table 4 illustratesanother example of the index table 212, and Table 5 illustrates anotherexample of the L2P table L2P_Table(1), where Table 4 is an updatedversion of Table 1, and Table 5 is an updated version of Table 2. Withregard to the logical address LBA(NL), the memory controller 110 mayperform a re-write operation at a second time point which is later thanthe first time point, and may update the index table 212 and the L2Ptable L2P_Table(1) as indicated in Table 4 and Table 5, respectively, tocorrespond to the latest status of the usage of the NV memory 120, wherethe L2P-table index {B:5, P:3} has been changed to the L2P-table index{B:5, P:8} (as shown in the upper right corner of Table 4) and themapping information {B:6, P:0} has been changed to the mappinginformation {B:6, P:5} (as shown in the upper right corner of Table 5).For example, the memory controller 110 may store the L2P tableL2P_Table(1) in the physical page PAGE(8) of the physical block BLOCK(5)as indicated by the L2P-table index {B:5, P:8}.

Afterward, the host device 50 may send a read command to the memorydevice 100, to ask for the target data such as the data of the logicaladdress LBA(NL). The host device 50 may also send the combination of themapping information {B:6, P:0} and the L2P-table index {B:5, P:3} to thememory device 100. For the case that the corresponding internal mappinginformation such as that of this combination is incorrect, the memorycontroller 110 may utilize its own version of internal mappinginformation, such as the correct L2P-table index in the index table 212(e.g. the L2P-table index {B:5, P:8}) and the local L2P address mappingtable that is found through the correct L2P-table index in the indextable 212 (e.g. the L2P table L2P_Table(1) that is found through theL2P-table index {B:5, P:8}). As a result, the memory controller 110 mayobtain the correct version of the target data in the physical pagePAGE(5) of the physical block BLOCK(6) as indicated by the mappinginformation {B:6, P:5}, rather than the old version of the target datain the physical page PAGE(0) of the physical block BLOCK(6) as indicatedby the mapping information {B:6, P:0}.

According to some embodiments, the block and page indexes in any of theL2P-table indexes {B:5, P:3}, {B:5, P:4}, {B:5, P:5}, {B:5, P:6}, {B:5,P:7}, etc. of Table 1 may represent a physical address of thecorresponding physical page of the corresponding physical block, but thepresent invention is not limited thereto. According to some embodiments,the block and page indexes in any of the mapping information {B:6,P:0},{B:6, P:1},{B:6, P:2},{B:6, P:3}, {B:6, P:4}, etc. of Table 2 mayrepresent a physical address of the corresponding physical page of thecorresponding physical block, but the present invention is not limitedthereto.

FIG. 6 illustrates a working flow of the method for performing accessmanagement in the memory device according to an embodiment of thepresent invention.

In Step 510, the memory device 100 may receive the host commandREAD_CMD, the associated logical address REQUEST_LBA, the L2P-tableindex INDEX_HOI, and the mapping information L2P_Info from the hostdevice 50. According to this embodiment, the read command may be takenas an example of the host command READ_CMD, the logical address of thetarget data may be taken as an example of the logical addressREQUEST_LBA, the L2P-table index sent by the host device 50 and storedin the HOI buffer 214 may be taken as an example of the L2P-table indexINDEX_HOI, and the set of L2P address mapping information (e.g. the MI)of the target data, such as the set of L2P address mapping information(e.g. the MI) sent by the host device 50 and stored in the HOI buffer214, may be taken as an example of the mapping information L2P_Info, butthe present invention is not limited thereto. For example, when the hostdevice 50 is operating abnormally, the mapping information L2P_Info mayhave been altered or may have become non-related to the target data. Inanother example, the host device 50 is operating normally, but themapping information L2P_Info may have become out of date.

In Step 512, the memory controller 110 may check whether the idealversion of the mapping information L2P_Info (e.g. the MI shown in FIG. 3) exists in the RAM 116 of the memory device 100. This may beimplemented according to one or more of the control schemes mentionedabove (e.g. the dual-read control scheme shown in FIG. 3 , the HOIchecking control scheme shown in FIG. 4 , and/or the RAM-sharing controlscheme shown in FIG. 5 ), but the present invention is not limitedthereto. According to this embodiment, the memory controller 110 mayutilize its own version of internal mapping information, such as the setof L2P address mapping information (e.g. the MI) pointing toward thetarget data and available in the temporary local L2P address mappingtable 211, as the ideal version of the mapping information L2P_Info,where the set of L2P address mapping information (e.g. the MI) can beobtained from the local L2P address mapping table that is found throughthe correct L2P-table index in the index table 212. When the idealversion of the mapping information L2P_Info exists in the RAM 116 of thememory device 100, Step 516 is entered; otherwise, Step 513 is entered.

In Step 513, the memory controller 110 may check whether the L2P-tableindex INDEX_INSIDE and the L2P-table index INDEX_HOI are equivalent toeach other. According to this embodiment, the aforementioned correctL2P-table index in the index table 212 may be taken as an example of theL2P-table index INDEX_INSIDE. When the L2P-table index INDEX_INSIDE andthe L2P-table index INDEX_HOI are equivalent to each other (which mayindicate that the mapping information L2P_Info is correct), Step 517 isentered; otherwise (which may indicate that the mapping informationL2P_Info is incorrect), Step 514 is entered.

In Step 514, the memory controller 110 may load the L2P table such asthat read in the first read operation mentioned above. For example, in asituation where the mapping information L2P_Info has become out of date,the memory controller 110 may prevent using the mapping informationL2P_Info as the reference for reading the target data.

In Step 516, the memory controller 110 may read the target data (e.g.the data read in the second read operation) from the physical page.

In Step 517, the memory controller 110 may read the target data (e.g.the data read in the single read operation) from the physical pageaccording to the mapping information L2P_Info.

In Step 520, the memory controller 110 may send the target data to thehost device 50. For example, no matter whether the mapping informationL2P_Info has become out of date, the memory controller 110 can correctlyread the target data and send out requested data (e.g. the target data)to the host device 50 as usual.

According to this embodiment, the combination of the host commandREAD_CMD and the logical address REQUEST_LBA mentioned in Step 510 maybe directed to a request of accessing the target data corresponding tothe logical address REQUEST_LBA from the NV memory 120. With regard tothe request of accessing the target data corresponding to the logicaladdress REQUEST_LBA from the NV memory 120, the memory controller 110may perform at least one checking operation (e.g. one or more checkingoperations) such as that of Steps 512 and 513 to obtain at least onechecking result such as that of Steps 512 and 513, for determiningwhether to load the L2P table mentioned in Step 514 from the NV memory120 to the RAM 116, where the L2P table may comprise the address mappinginformation for accessing the target data, such as the set of L2Paddress mapping information (e.g. the MI). In addition, the checkingresult of Step 512 may indicate whether the ideal version of the mappinginformation L2P_Info exists in the RAM 116 or not. When Step 516 isentered based on this checking result, the memory controller 110 mayread the target data from the NV memory 120 according to the idealversion of the mapping information L2P_Info in Step 516, where thelatest version (e.g. a loaded version or an updated version) of the L2Ptable is available in the RAM 116 when reading the target data from theNV memory 120 is performed, and the ideal version of the mappinginformation L2P_Info (e.g. the MI shown in FIG. 3 ) is also available inthe RAM 116. For example, before the checking operation of Step 512 isperformed, the L2P table may have been loaded into the RAM 116 as theloaded version of the L2P table, so Step 516 may be entered, but thepresent invention is not limited thereto. Additionally, the checkingresult of Step 513 may indicate whether the L2P-table index INDEX_INSIDEand the L2P-table index INDEX_HOI are equivalent to each other or not.When Step 514 is entered based on this checking result, the memorycontroller 110 may load the L2P table into the RAM 116 as the loadedversion of the L2P table in Step 514, and may read the target data fromthe NV memory 120 according to the loaded version of the L2P table inStep 516, where the latest version (e.g. the loaded version) of the L2Ptable is available in the RAM 116 when reading the target data from theNV memory 120 is performed, and the ideal version of the mappinginformation L2P_Info (e.g. the MI shown in FIG. 3 ) is also available inthe RAM 116. When Step 517 is entered based on this checking result, thememory controller 110 may read the target data from the NV memory 120according to the mapping information L2P_Info (e.g. the MI shown in FIG.4 ) in Step 517, where the mapping information L2P_Info is available inthe RAM 116. In some examples, the memory controller 110 may update theL2P table (e.g. the loaded version of the L2P table) to generate theupdated version of the L2P table.

Regarding the HOI mentioned above, the memory controller 110 may sendthe set of internal mapping information of the memory device 100 towardthe host device 50 as the HOI, for enhancing performance of the memorydevice 100, where the set of internal mapping information is related tomapping logical addresses to multiple physical addresses of the NVmemory 120. This is typically performed in advance. After sending theset of internal mapping information of the memory device 100 toward thehost device 50 as the HOI, the memory controller 110 may receive thehost command READ_CMD, the logical address REQUEST_LBA, the L2P-tableindex INDEX_HOI, and the mapping information L2P_Info from the hostdevice 50, where the mapping information L2P_Info is related to mappingthe logical address REQUEST_LBA to a physical address of the NV memory120. For example, the host device 50 may sends the L2P-table indexINDEX_HOI and the mapping information L2P_Info toward the memory device100 as additional information related to the request of accessing thetarget data corresponding to the logical address REQUEST_LBA from the NVmemory 120. In addition, the mapping information L2P_Info may bereceived as at least one portion (e.g. a portion or all) of the HOI, andmore particularly, may be received as the portion of the HOI regardlessof the correctness of the mapping information L2P_Info, since the memorycontroller 110 can check the correctness of the mapping informationL2P_Info through the operation of Step 513. The host device 50 may sendthe mapping information L2P_Info toward the memory device 100 forguiding the memory device 100 to access the target data according to themapping information L2P_Info, but the memory device 100 (e.g. the memorycontroller 110) may reject the guidance when needed (e.g. in a situationwhere Step 514 is entered). For example, when the physical address isdirected to the target data (which means the mapping informationL2P_Info is correct), the L2P-table index INDEX_INSIDE and the L2P-tableindex INDEX_HOI are equivalent to each other, so Step 517 is entered. Asa result, when the L2P-table index INDEX_INSIDE and the L2P-table indexINDEX_HOI are equivalent to each other, the memory controller 110 skipsloading the L2P table from the NV memory 120 to the RAM 116 of thememory device 100 and performs the operation of Step 517. In anotherexample, when the physical address is not directed to the target data(which means the mapping information L2P_Info is incorrect), theL2P-table index INDEX_INSIDE and the L2P-table index INDEX_HOI are notequivalent to each other, so Step 514 is entered. As a result, when theL2P-table index INDEX_INSIDE and the L2P-table index INDEX_HOI are notequivalent to each other, the memory controller 110 loads the L2P tablefrom the NV memory 120 to the RAM 116 of the memory device 100 in Step514. With aid of the checking result of Step 513, the memory controller110 that controls the operations of the memory device 100 according tothe present invention method can guarantee that the memory device 100can operate properly in various situations, respectively, where variousgoals such as optimal performance, high security, budget control, etc.can be achieved.

Those skilled in the art will readily observe that numerousmodifications and alterations of the device and method may be made whileretaining the teachings of the invention. Accordingly, the abovedisclosure should be construed as limited only by the metes and boundsof the appended claims.

What is claimed is:
 1. A method for performing access management in amemory device, the memory device comprising a non-volatile (NV) memory,the NV memory comprising at least one NV memory element, the methodcomprising: sending a plurality of sets of mapping information andlogical-to-physical (L2P)-table index of the memory device to a hostdevice, each set of mapping information and L2P-table index among theplurality of sets of mapping information and L2P-table index comprisingmapping information and an L2P-table index, wherein the mappinginformation in said each set of mapping information and L2P-table indexis related to mapping a logical address to a physical address of the NVmemory, and the L2P-table index in said each set of mapping informationand L2P-table index points to a physical address where a correspondingL2P table among multiple L2P tables is stored in the NV memory;receiving a read command carrying at least one set of mappinginformation and L2P-table index among the plurality of sets of mappinginformation and L2P-table index and a logical address, from the hostdevice, wherein the read command is directed to a request of accessingtarget data corresponding to the logical address carried by the readcommand from the NV memory; with regard to the request of accessing thetarget data corresponding to the logical address carried by the readcommand from the NV memory, according to at least one checking result,determining whether to load a first L2P table among the multiple L2Ptables from the NV memory to a random access memory (RAM) of the memorydevice, wherein the first L2P table comprises address mappinginformation for accessing the target data, and the at least one checkingresult indicates whether a first L2P-table index stored in the RAM andpointing toward the first L2P table and a second L2P-table index amongat least one L2P table index in the at least one set of mappinginformation and L2P-table index carried by the read command sent fromthe host device are equivalent to each other; in response to the atleast one checking result indicating that the first L2P-table index andthe second L2P-table index are equivalent to each other, using themapping information in the at least one set of mapping information andL2P-table index carried by the read command sent from the host device toread the target data from the NV memory; and sending the target data tothe host device.
 2. The method of claim 1, wherein the read command, thelogical address carried by the read command, and the target datarepresent a first read command, a first logical address carried by thefirst read command, and first target data, respectively, the at leastone set of mapping information and L2P-table index represents at leastone first set of mapping information and L2P-table index, and the atleast one checking result represents at least one first checking result;and the method further comprises: receiving a second read commandcarrying at least one second set of mapping information and L2P-tableindex among the plurality of sets of mapping information and L2P-tableindex and a second logical address, from the host device, wherein thesecond read command is directed to a request of accessing second targetdata corresponding to the second logical address carried by the secondread command from the NV memory; with regard to the request of accessingthe second target data corresponding to the second logical addresscarried by the second read command from the NV memory, according to atleast one second checking result, determining whether to load a secondL2P table among the multiple L2P tables from the NV memory to the RAM ofthe memory device, wherein the second L2P table comprises addressmapping information for accessing the second target data, and the atleast one second checking result indicates whether a third L2P-tableindex stored in the RAM and pointing toward the second L2P table and afourth L2P-table index among at least one L2P table index in the atleast one second set of mapping information and L2P-table index carriedby the second read command sent from the host device are equivalent toeach other; in response to the at least one second checking resultindicating that the third L2P-table index and the fourth L2P-table indexare not equivalent to each other, loading the second L2P table from theNV memory to the RAM, and using the second L2P table to read the secondtarget data from the NV memory; and sending the second target data tothe host device.
 3. The method of claim 2, wherein the mappinginformation in the at least one second set of mapping information andL2P-table index carried by the second read command sent from the hostdevice is related to mapping the second logical address to a secondphysical address of the NV memory; and when the second physical addressis not directed to the second target data, the third L2P-table index andthe fourth L2P-table index are not equivalent to each other.
 4. Themethod of claim 3, wherein the mapping information in the at least onefirst set of mapping information and L2P-table index carried by thefirst read command sent from the host device is related to mapping thefirst logical address to a first physical address of the NV memory; andwhen the first physical address is directed to the first target data,the first L2P-table index and the second L2P-table index are equivalentto each other.
 5. The method of claim 1, wherein the read command andthe logical address carried by the read command represent a first readcommand and a first logical address carried by the first read command,respectively, and the mapping information in the at least one set ofmapping information and L2P-table index carried by the read command sentfrom the host device is related to mapping the first logical address toa first physical address of the NV memory; and when the first physicaladdress is directed to the target data, the first L2P-table index andthe second L2P-table index are equivalent to each other.
 6. The methodof claim 1, wherein the step of sending the plurality of sets of mappinginformation and L2P-table index of the memory device to the host devicefurther comprises: sending at least one set of internal mappinginformation of the memory device toward the host device as host-ownedinformation (HOI), wherein the at least one set of internal mappinginformation comprises the plurality of sets of mapping information andL2P-table index of the memory device; wherein the step of receiving theread command carrying the at least one set of mapping information andL2P-table index among the plurality of sets of mapping information andL2P-table index and the logical address from the host device furthercomprises: after sending the at least one set of internal mappinginformation of the memory device toward the host device as the HOI,receiving the read command carrying the at least one set of mappinginformation and L2P-table index among the plurality of sets of mappinginformation and L2P-table index and the logical address.
 7. The methodof claim 6, wherein the at least one set of mapping information andL2P-table index is received as at least one portion of the HOI.
 8. Amemory device, comprising: a non-volatile (NV) memory, arranged to storeinformation, wherein the NV memory comprises at least one NV memoryelement; and a controller, coupled to the NV memory, arranged to controloperations of the memory device, wherein the controller comprises: aprocessing circuit, arranged to control the controller according to aplurality of host commands from a host device, to allow the host deviceto access the NV memory through the controller, wherein: the controllersends a plurality of sets of mapping information and logical-to-physical(L2P)-table index of the memory device to the host device, each set ofmapping information and L2P-table index among the plurality of sets ofmapping information and L2P-table index comprising mapping informationand an L2P-table index, wherein the mapping information in said each setof mapping information and L2P-table index is related to mapping alogical address to a physical address of the NV memory, and theL2P-table index in said each set of mapping information and L2P-tableindex points to a physical address where a corresponding L2P table amongmultiple L2P tables is stored in the NV memory; the controller receivesa read command carrying at least one set of mapping information andL2P-table index among the plurality of sets of mapping information andL2P-table index and a logical address, from the host device, wherein theread command is directed to a request of accessing target datacorresponding to the logical address carried by the read command fromthe NV memory; with regard to the request of accessing the target datacorresponding to the logical address carried by the read command fromthe NV memory, according to at least one checking result, the controllerdetermines whether to load a first L2P table among the multiple L2Ptables from the NV memory to a random access memory (RAM) of the memorydevice, wherein the first L2P table comprises address mappinginformation for accessing the target data, and the at least one checkingresult indicates whether a first L2P-table index stored in the RAM andpointing toward the first L2P table and a second L2P-table index amongat least one L2P table index in the at least one set of mappinginformation and L2P-table index carried by the read command sent fromthe host device are equivalent to each other; in response to the atleast one checking result indicating that the first L2P-table index andthe second L2P-table index are equivalent to each other, the controlleruses the mapping information in the at least one set of mappinginformation and L2P-table index carried by the read command sent fromthe host device to read the target data from the NV memory; and thecontroller sends the target data to the host device.
 9. The memorydevice of claim 8, wherein the read command, the logical address carriedby the read command, and the target data represent a first read command,a first logical address carried by the first read command, and firsttarget data, respectively, the at least one set of mapping informationand L2P-table index represents at least one first set of mappinginformation and L2P-table index, and the at least one checking resultrepresents at least one first checking result, wherein: the controllerreceives a second read command carrying at least one second set ofmapping information and L2P-table index among the plurality of sets ofmapping information and L2P-table index and a second logical address,from the host device, wherein the second read command is directed to arequest of accessing second target data corresponding to the secondlogical address carried by the second read command from the NV memory;with regard to the request of accessing the second target datacorresponding to the second logical address carried by the second readcommand from the NV memory, according to at least one second checkingresult, the controller determines whether to load a second L2P tableamong the multiple L2P tables from the NV memory to the RAM of thememory device, wherein the second L2P table comprises address mappinginformation for accessing the second target data, and the at least onesecond checking result indicates whether a third L2P-table index storedin the RAM and pointing toward the second L2P table and a fourthL2P-table index among at least one L2P table index in the at least onesecond set of mapping information and L2P-table index carried by thesecond read command sent from the host device are equivalent to eachother; in response to the at least one second checking result indicatingthat the third L2P-table index and the fourth L2P-table index are notequivalent to each other, the controller loads the second L2P table fromthe NV memory to the RAM, and uses the second L2P table to read thesecond target data from the NV memory; and the controller sends thesecond target data to the host device.
 10. An electronic devicecomprising the memory device of claim 8, and further comprising: thehost device, coupled to the memory device, wherein the host devicecomprises: at least one processor, arranged for controlling operationsof the host device; and a power supply circuit, coupled to the at leastone processor, arranged for providing power to the at least oneprocessor and the memory device; wherein the memory device provides thehost device with storage space.
 11. A controller of a memory device, thememory device comprising the controller and a non-volatile (NV) memory,the NV memory comprising at least one NV memory element, the controllercomprising: a processing circuit, arranged to control the controlleraccording to a plurality of host commands from a host device, to allowthe host device to access the NV memory through the controller, wherein:the controller sends a plurality of sets of mapping information andlogical-to-physical (L2P)-table index of the memory device to the hostdevice, each set of mapping information and L2P-table index among theplurality of sets of mapping information and L2P-table index comprisingmapping information and an L2P-table index, wherein the mappinginformation in said each set of mapping information and L2P-table indexis related to mapping a logical address to a physical address of the NVmemory, and the L2P-table index in said each set of mapping informationand L2P-table index points to a physical address where a correspondingL2P table among multiple L2P tables is stored in the NV memory; thecontroller receives a read command carrying at least one set of mappinginformation and L2P-table index among the plurality of sets of mappinginformation and L2P-table index and a logical address, from the hostdevice, wherein the read command is directed to a request of accessingtarget data corresponding to the logical address carried by the readcommand from the NV memory; with regard to the request of accessing thetarget data corresponding to the logical address carried by the readcommand from the NV memory, according to at least one checking result,the controller determines whether to load a first L2P table among themultiple L2P tables from the NV memory to a random access memory (RAM)of the memory device, wherein the first L2P table comprises addressmapping information for accessing the target data, and the at least onechecking result indicates whether a first L2P-table index stored in theRAM and pointing toward the first L2P table and a second L2P-table indexamong at least one L2P table index in the at least one set of mappinginformation and L2P-table index carried by the read command sent fromthe host device are equivalent to each other; in response to the atleast one checking result indicating that the first L2P-table index andthe second L2P-table index are equivalent to each other, the controlleruses the mapping information in the at least one set of mappinginformation and L2P-table index carried by the read command sent fromthe host device to read the target data from the NV memory; and thecontroller sends the target data to the host device.
 12. The controllerof claim 11, wherein the read command, the logical address carried bythe read command, and the target data represent a first read command, afirst logical address carried by the first read command, and firsttarget data, respectively, the at least one set of mapping informationand L2P-table index represents at least one first set of mappinginformation and L2P-table index, and the at least one checking resultrepresents at least one first checking result, wherein: the controllerreceives a second read command carrying at least one second set ofmapping information and L2P-table index among the plurality of sets ofmapping information and L2P-table index and a second logical address,from the host device, wherein the second read command is directed to arequest of accessing second target data corresponding to the secondlogical address carried by the second read command from the NV memory;with regard to the request of accessing the second target datacorresponding to the second logical address carried by the second readcommand from the NV memory, according to at least one second checkingresult, the controller determines whether to load a second L2P tableamong the multiple L2P tables from the NV memory to the RAM of thememory device, wherein the second L2P table comprises address mappinginformation for accessing the second target data, and the at least onesecond checking result indicates whether a third L2P-table index storedin the RAM and pointing toward the second L2P table and a fourthL2P-table index among at least one L2P table index in the at least onesecond set of mapping information and L2P-table index carried by thesecond read command sent from the host device are equivalent to eachother; in response to the at least one second checking result indicatingthat the third L2P-table index and the fourth L2P-table index are notequivalent to each other, the controller loads the second L2P table fromthe NV memory to the RAM, and uses the second L2P table to read thesecond target data from the NV memory; and the controller sends thesecond target data to the host device.